Heavy Period & Pregnancy Test: Can a Period Cause a False Positive?

A pregnancy test detects the presence of human chorionic gonadotropin (hCG), a hormone produced by the developing placenta. hCG levels typically start to rise about 6 days after conception and double every 48 to 72 hours. However, it is possible for hCG levels to remain elevated for several weeks after a miscarriage or pregnancy loss. This can cause a pregnancy test to come up positive even if you have just had a heavy period.

If you have had a heavy period and are concerned about the possibility of being pregnant, it is important to talk to your doctor. They can order a blood test to measure your hCG levels and determine if you are pregnant.